Organic Cation Modulation in Hybrid Zirconium Halides for High‐Performance Flexible X‐Ray Imaging

Abstract Exploiting novel materials featuring high‐quality zero‐dimensional structure, remarkable lattice stability, and minimal defects represents an efficacious strategy for enhancing the detection performance of X‐ray scintillators. Here, we design and synthesize two novel zirconium‐based organic‐inorganic hybrid metal halides (OIMHs), C 14 H 40 N 4 ZrCl 8 and C 6 H 16 N 2 ZrCl 6 . Based on the steric hindrance effect of organic cations, the distance between [ZrCl 6 ] 2− polyhedra was designed, and the electronic coupling interactions among polyhedra were adjusted, thus precisely engineering excellent zero‐dimensional materials. Simultaneously, the stronger N─H + ···Cl − bond is introduced to avoid structural instabilities and more defects due to the bigger organic cation in C 14 H 40 N 4 ZrCl 8 . As expected, C 14 H 40 N 4 ZrCl 8 exhibits more remarkable luminescence behavior compared to C 6 H 16 N 2 ZrCl 6 . The photophysics process involving self‐trapped excitons and defects is elaborately expounded using first‐principles calculations, luminescence properties, and stabilities. Finally, a flexible and large‐area scintillation screen based on C 14 H 40 N 4 ZrCl 8 is fabricated and attains a high spatial resolution of 21.35 lp mm −1 and a lower limit of detection of 2.270 µGy air s −1 , outperforming the resolution of most blue‐emitting scintillation screens. These results imply that the zirconium‐based OIMHs possess significant potential applications for medical diagnostics, security scanning, and non‐destructive testing.